GB370836A - Improvements in friction ratchet clutches, gears and detents - Google Patents

Abstract

370,836. Friction ratchet clutches. AKTIEBOLAGET VOLVO, Gothenburg, Sweden. Oct. 12, 1931, No. 28322. Convention date, Oct. 13, 1930. [Classes 80 (ii) and 80 (iii).] The coil of a coil clutch or detent is arranged to press resiliently against the member to which it is connected with a pressure which is greatest near the point of connection and diminishes regularly towards the free end or ends, in order that, in action, the winding and unwinding may take place progressively from the end of the coil without undue slip. A coil 2, Fig. 1, formed from a steel &c. band of rectangular or round section is secured at one end 4 to a driving or driven member 3, against which it bears when idle with a pressure decreasing towards the free end, the last turn or turns being reduced to grip the driven or driving shaft 1. The coil may be secured to the inner member and be adapted to grip the outer. The effect may be produced by forcing the coil under stress into or over the member, either the band being of decreasing thickness towards the free end, as shown, or the coil having a conical form in the free state. A coil 9, Fig. 7, may be secured at its mid-point to an outer member 10, its free ends being engageable alternatively with coned surfaces 14, 15 on a control sleeve 12 splined to the inner member 11, to provide a reversible drive. In the midposition of the sleeve, both halves of the coil are free. To avoid axial reaction on the sleeve, it may be moved far enough to bring a cylindrical part into contact with the coil. In a modification, the coil is secured to the part 11 and the sleeve splined to slide in the outer part 10. Fig. 11 shows a variable-speed drive incorporating a pair of such reversible clutches. An electromotor-driven shaft 17 carries a compound eccentric 19, 30, the throw of which can be altered by the engagement of a cotter 31 in various keyways 32. Eccentric straps 21, 24 are connected to lugs 22, 25 respectively on the outer members of the two reversible clutches, which function alternately on the up and down strokes of the lugs and are provided with a common coned control sleeve 28 splined to the driven shaft 27. A number of sets may be used to secure uniform rotation. By forming one cone 40, Fig. 9, on an independent sleeve slidable on the sleeve 12 by a lever 42 mounted on the main operating-lever 43, the reversible clutch may additionally be rendered bidirectional, this modification being applicable also to the form in which the coil is secured to the shaft. In order to obviate reduction of the constant grip of the free end on the shaft or outer member due to axial jolting, the coil may be axially compressed by a nut. Instead of gripping directly on the shaft or outer member, the free end may bear on a positivelyrotated or fixed sleeve, or alternatively or additionally may be actuated by a shoe &c. attached to the coil. The invention is applicable in all its forms as a reversible or other one-way clutch between two shafts or as a brake between, say, a shaft and a fixed machine frame.